Decibel Converter
Convert a power or amplitude ratio into decibels.
Runs in your browser. Nothing is uploaded — your input is processed on this device and discarded when you close the tab.
Decibel Converter
How to use this tool
- Enter the ratio of output to input.
- Choose whether it is a power ratio or an amplitude ratio.
- Press Generate to see the level in decibels.
Worked example
A power ratio of 100 gives 10 times log10 of 100, which is 20.00 dB. An amplitude ratio of 2 gives 20 times log10 of 2, which is 6.02 dB.
What this tool does not do / Limits
This converts a plain ratio into decibels and does not measure sound, set a reference level or judge hearing safety. A decibel figure only has a physical meaning once the reference it is measured against is known.
Frequently asked questions
Why do power and amplitude use different multipliers?
Power grows with the square of amplitude, so the log formulas differ by a factor of two: 10 for power ratios and 20 for amplitude ratios, giving the same decibel result for matching quantities.
What does a negative result mean?
A ratio below 1 means the output is smaller than the input, so the decibel value is negative, showing a loss rather than a gain.
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